Electric water pump with coolant passage

ABSTRACT

An electric water pump includes an electric motor having a stator which generates an electromagnetic field by control signals supplied from a pump driver. A rotor rotates by the electromagnetic field generated by the stator. An impeller is connected to and rotates with the rotor to circulate a coolant. An inside space of the electric water pump may include a motor room in which the electric motor is disposed, a volute room in which the impeller is positioned, and a pump driver room in which the pump driver is positioned.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of priority to Korean Patent Application Number 10-2014-0107126 filed on Aug. 18, 2014, the entire contents of which application are incorporated herein for all purposes by this reference.

TECHNICAL FIELD

The present disclosure relates to an electric water pump, and more particularly, to an electric water pump having a separate coolant flow passage.

BACKGROUND

A water pump of a vehicle circulates a coolant through an engine, a heater, etc. for cooling the engine and heating an inside of the vehicle. The coolant in the water pump recirculates after discharged from the water pump and exchanging heat with the engine, the heater, a radiator, or the like.

The water pump is classified largely into a mechanical water pump and an electric water pump.

The mechanical water pump operates according to rotation of a crankshaft, i.e., an engine revolutions per minute (RPM) by being connected with a pulley fixed to the crankshaft of the engine. Therefore, a flow rate of the coolant discharged from the mechanical water pump is determined according to the engine RPM.

Here, the flow rate of the coolant necessary for the heater, the radiator, etc. is determined without relation to the engine RPM. In a low engine speed region, since the heater and the radiator cannot operate normally, the engine speed needs to be increased for a normal operation of the heater and the radiator, thus increasing fuel consumption.

The electric water pump operates by a motor controlled through a controller. Therefore, the electric water pump can determine the flow rate of the coolant, regardless of the engine RPM.

However, waterproof function is required for components used in the electric water pump to improve performance and durability of the electric water pump.

The demand for the electric water pump has been increasing. Accordingly, technologies for improving performance and durability of the electric water pump have been developing.

The electric water pump requires a separate pump driver to control an electric motor, and the pump driver is assembled integrally with the electric water pump as a printed circuit board (PCB) in which electrical elements of a microprocessor, a condenser, a resistor, a switch, etc. are integrated.

The PCB is mounted in a pump driver room which is formed at a rear or side portion of the electric water pump. The pump driver room is prevented from water flowing therein by having a sealed structure.

In general, when there is a high load during driving due to a high load of an electric motor, temperature of the PCB also increases. In addition, since high temperature of about 150 degrees centigrade is maintained in a periphery of the engine on which the electric water pump is mounted, temperature of the pump driver room and the PCB of the electric water pump is high.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY

An aspect of the present inventive concept provides a cooling structure of an electric water pump capable of increasing heat release efficiency of a pump driver and a pump driver room by forming a coolant flow passage in a bulkhead mounted between a motor room and the pump driver room of the electric water pump and by running coolant through the coolant flow passage.

According to an exemplary embodiment of the present inventive concept, an electric water pump includes an electric motor having a stator which generates an electromagnetic field by control signals supplied from a pump driver. A rotor rotates by the electromagnetic field generated by the stator. An impeller is connected to and rotates with the rotor to circulate a coolant An inside space of the electric water pump may include a motor room in which the electric motor is positioned, a volute room in which the impeller is positioned, and a pump driver room in which the pump driver is positioned. The electric water pump may further include an insulation pad for insulating the pump driver from the bulkhead.

The electric water pump may further include a first cooling passage formed in one side of a water pump housing or a motor room cover for sealing the motor room from outside. A second cooling passage has one end connected to the first cooling passage and penetrates the bulkhead. A third cooling passage is connected to another end of the second cooling passage and formed in another side of the water pump housing or the motor room cover. A portion of coolant passing through the volute room flows through the first cooling passage, the second cooling passage, and the third cooling passage.

The first cooling passage and the third cooling passage may be formed in a length direction of the electric water pump, and the second cooling passage may pass through a middle of the bulkhead.

At least one coolant flow passage may be integrally formed by the first cooling passage, the second cooling passage, and the third cooling passage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a longitudinal section of an electric water pump according to an exemplary embodiment of the present inventive concept without a separate coolant flow passage.

FIG. 2 is a schematic diagram showing a longitudinal section of an electric water pump according to another exemplary embodiment of the present inventive concept with a separate coolant flow passage formed therein.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present inventive concept, examples of which are illustrated in the accompanying drawings and described below. While the disclosure will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the inventive concept is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements, and the name of a component does not limit the function of the component concerned.

FIG. 1 is a schematic diagram showing a longitudinal section of an electric water pump according to an exemplary embodiment of the present inventive concept without a separate coolant flow passage.

Referring to FIG. 1, an electric water pump 1 according to the present disclosure may comprise an electric motor 5 having a stator 10 generating an electromagnetic field by control signals supplied from a pump driver 40. A rotor 20 rotates by the electromagnetic field generated by the stator 10. An impeller 30 is connected to and rotates with the rotor 20 to circulate a coolant.

The pump driver 40 is a circuit board in which electrical elements 41 of a microprocessor, a condenser, a resistor, and a switch, etc. are integrated, and may be a printed circuit board (PCB).

An inside space of the electric water pump 1 may include a motor room 50 in which the electric motor 5 is disposed, a volute room 60 in which the impeller 30 is disposed, and a pump driver room 70 in which the pump driver 40 is disposed.

An exterior surface of the electric water pump 1 is formed by a water pump housing 3 and a volute room cover 63. The water pump housing 3 and the volute room cover 63 respectively close and seal the motor room 50 and the volute room 60 from outside of the electric water pump 1.

However, it is not limited thereto that the motor room 50 may be closed and sealed by a separate cover with respect to the external space.

In FIG. 1, a separate motor room cover 2 is used together with a water pump housing 3.

Referring to FIG. 1, the electric water pump 1 according to an exemplary embodiment of the present inventive concept may further include a separation wall 90 separately forming a rotor room 80 in the motor room 50 such that the rotor 20 is isolated from the motor room 50. A bulkhead 100 separates the motor room 50 and the pump driver room 70 such that the motor room 50 and the pump driver room 70 are closed and sealed with respect to each other by the bulkhead 100. A cap 110 is mounted at a front surface of the bulkhead 100 such that the cap 110 supports one end of the separation wall 90.

In this case, a front surface portion of the rotor room 80 may fluidly communicate with the volute room 60 such that the coolant flows into the rotor room 80.

Referring to FIG. 1, operation principles of the electric water pump 1 according to the present disclosure and heat transfer paths of the pump driver room 70 will be explained hereinafter.

The volute room 60 is a space in which a coolant flows through an inlet 61 and an outlet 62.

The inlet 61 is in general connected to a radiator (not shown). A cooled coolant flows into the volute room 60 from the radiator through the inlet 61 when the impeller 30 starts rotating by operation of the electric motor 5, in which the impeller 30 is connected to the rotor 20.

The outlet 62 is in general connected to a water jacket (not shown) of the engine, and the impeller 30 supplies the coolant flowing into the volute room 60 to the water jacket through the outlet 62 after pressurizing the coolant (arrows in the volute room 60 of FIG. 1 show a flowing direction of the coolant).

A portion of the coolant flowing in the volute room 60 may flow into the rotor room 80 fluidly communicating with the volute room 60 (arrows in the rotor room 80 show for flow of coolant).

Thus, heat generated from the pump driver 40 passes via the pump driver 40, the bulkhead 100, the cap 110, and the separation wall 90 sequentially and is transferred to the coolant flowing into the rotor room 80.

The electric water pump 1 may further include an insulation pad 120 for insulating the pump driver 40 from the bulkhead 100.

Referring to FIG. 1, the heat generated from the pump driver 40 passes the pump driver 40, the insulation pad 120, the bulkhead 100, the cap 110, and the separation wall 90 sequentially and is transferred to the coolant flowing into the rotor room 80 (heat transfer paths are expressed as arrows in FIG. 1).

According to the exemplary embodiment of the present inventive concept as illustrated in FIG. 1, enough heat release cannot be achieved because of structures limiting the heat transfer to coolant and the heat transfer path is relatively long. Thus, a separate coolant flow passage may be necessary for more effective heat release of the pump driver 40 and the pump driver room 70.

FIG. 2 is a schematic diagram showing a longitudinal section of an electric water pump according to another exemplary embodiment of the present inventive concept with a separate coolant flow passage formed therein.

Same reference numerals indicate same elements used throughout the disclosure.

Referring to FIG. 2, an electric water pump 1 according to another exemplary embodiment of the present inventive concept may further include a first cooling passage 201 formed in one side of the water pump housing 3 or the motor room cover 2 f or sealing the motor room 50 from outside of the electric water pump 1. A second cooling passage 202 has one end connected to the first cooling passage 201 and penetrates the bulkhead 100. A third cooling passage 203 is connected to another end of the second cooling passage 202 and formed in another side of the water pump housing 3 or the motor room cover 2.

According to another exemplary embodiment of the present inventive concept, the first cooling passage 201 and the third cooling passage 203 in the water pump housing 3 are formed by drilling. In this case, the bulkhead 100 may be integrally formed in the water pump housing 3, and the second cooling passage 202 may be completely sealed from outside.

Therefore, the first cooling passage 201, the second cooling passage 202, and the third cooling passage 203 are connected with one another and integrally form the separate coolant flow passage. In addition, the bulkhead 100 may be separately formed from the water pump housing 3.

A portion of coolant passing through the volute room 60 may flow through the first cooling passage 201, the second cooling passage 202, and the third cooling passage 203.

The coolant flows into one end of the first cooling passage 201 which is a high pressure portion of the volute room 60, passes through the second cooling passage 202 connected to another end of the first cooling passage 201, and thereby receives heat generated from the pump driver 40.

Subsequently, the coolant may pass through the third cooling passage 203, and flows back into a low pressure portion of the volute room 60.

However, in another exemplary embodiment of the present inventive concept, the coolant may flow in an opposite direction depending on structural changes of the electric water pump 1, such as a change in a rotating direction of the impeller 30, etc.

Heat release effect is increased because the heat generated in the pump driver 40 passes only the bulkhead 100 or only the insulation pad 120, and is transferred to the coolant flowing through the second cooling passage 202.

The first cooling passage 201 and the third cooling passage 203 may be formed in a length direction of the electric water pump 1 for convenience of machining such as drilling for forming the coolant passages.

Although flow direction of the coolant for the first cooling passage 201 and the third cooling passage 203 may vary according to a machining process, as long as coolant flows into one end of the coolant flow passage, the coolant can flow out from another end thereof.

The second cooling passage 202 may pass through a middle of the bulkhead 100 since heat is generated intensively at a center portion of the pump driver 40.

The coolant flow passage integrally formed by the first cooling passage 201, the second cooling passage 202, and the third cooling passage 203 may be more than one. As long as the electric water pump 1 maintains structural-rigidity, the heat release effect of the pump driver 40 and the pump driver room 70 can be improved through the second cooling passage 202 enabled to pass through different portions of the bulkhead 100.

As explained in detail, according to the present disclosure, cooling of a pump driver and a pump driver room of an electric water pump can be effectively achieved.

While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the inventive concept is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 

What is claimed is:
 1. An electric water pump comprising: an electric motor having a stator which generates an electromagnetic field by control signals supplied from a pump driver, and a rotor which rotates by the electromagnetic field generated by the stator; and an impeller connected to and rotating with the rotor to circulate a coolant, wherein an inside space of the electric water pump includes: a motor room in which the electric motor is disposed; a volute room in which the impeller is disposed; and a pump driver room in which the pump driver is disposed.
 2. The electric water pump of claim 1, further comprising: a bulkhead separating the motor room and the pump driver room to seal the motor room and the pump driver room with respect to each other; a separation wall separately forming a rotor room inside the motor room to isolate the rotor from the motor room; and a cap mounted to a front surface of the bulkhead to support one end of the separation wall, wherein a front side of the rotor room fluidly communicates with the volute room to flow the coolant into the rotor room.
 3. The electric water pump of claim 2, further comprising: an insulation pad for insulating the pump driver from the bulkhead.
 4. The electric water pump of claim 2, further comprising: a first cooling passage formed in one side of a water pump housing or a motor room cover for sealing the motor room from outside; a second cooling passage of which one end is connected to the first cooling passage, the second cooling passage penetrating the bulkhead; and a third cooling passage connected to another end of the second cooling passage and formed in another side of the water pump housing or the motor room cover, wherein a portion of the coolant passing through the volute room flows through the first cooling passage, the second cooling passage, and the third cooling passage.
 5. The electric water pump of claim 4, wherein the first cooling passage and the third cooling passage are formed in a length direction of the electric water pump.
 6. The electric water pump of claim 4, wherein the second cooling passage passes through a middle of the bulkhead.
 7. The electric water pump of claim 4, wherein at least one coolant flow passage is integrally formed by the first cooling passage, the second cooling passage, and the third cooling passage.
 8. The electric water pump of claim 1, wherein the volute room has an inlet and outlet through which the coolant flows by rotation of the impeller and flows out. 